Your commute might be killing you, according to a new study by researchers at Washington University in St. Louis.
That's because people who live more than 10 miles from their work are more likely to have high blood pressure than people with shorter commutes. People who commute more than 15 miles each way are much more likely to be obese, perhaps because people who commute that distance don't get enough daily activity.
"Most of the findings were fairly intuitive," says Christine Hoehner, the lead author of the study, which was published in the American Journal of Preventative Medicine. "But this is the first study to show that long commutes take away from exercise and lead to conditions that are strong predictors of diabetes, obesity, and some cancers."
Even long commuters who found ways to get enough exercise were more likely to have high blood pressure than people with shorter commutes who get the same amount of exercise. That may be because commuting is a highly stressful activity—a 2011 study by Swedish researchers found that people who had long commutes to work were more likely to divorce, experience neck pain, and loneliness.
The Washington University study surveyed nearly 4,300 people in the Dallas-Fort Worth and Austin areas, where roads regularly rank among the nation's most congested. Nearly one in five people surveyed commuted more than 20 miles each way; about half commute at least 10 miles each way.
"I think the traffic piece is important," Hoehner says. "Even with longer commutes, if you don't have the traffic, you don't have the day-to-day unpredictability and stress it causes."
Hoehner says it's likely that people who have long commutes have less time for exercise, sleep, and cooking, which can all lead to increased body-mass indexes and body fat content.
"That could be one of the mechanisms for these elevated numbers—they might not have the discretionary time to fit in exercise and cook healthy meals," she says. "People who have longer commutes would have to make an extra effort to find time for physical activity."
Outside of higher blood pressure numbers, long-commuters who can find time to exercise can mitigate most of the detrimental effects of their daily grind.
"The main message we're trying to get across is people need to find a way to build physical activity into their day, whether it's taking walking breaks at work, taking the stairs, or asking employers to be flexible about their schedules," she says.
Jason Koebler is a science and technology reporter for U.S. News & World Report. You can follow him on Twitter or reach him at firstname.lastname@example.org